Is it possible for an upstream to change license from a BSD-old to GPL? Consider the hypothesis that the product is a derivative work with a few old contributors. I see no reasons to do not relicense after addinga credits note as required in the BSD license.
New work could be licensed under the GPL, but if you mean the type with the advertising clauses by "BSD-old", you need to read http://www.gnu.org/licenses/license-list.html#OriginalBSD and http://www.gnu.org/philosophy/bsd.html
-- MJR/slef My Opinion Only and possibly not of any group I know. http://www.ttllp.co.uk/ for creative copyleft computing